Set Function.name for funcs in variables and properties as per spec.

Implements correct Function.name for cases like following:
 * `var x = function () { ... }`
 * `var obj = {prop: function () { ... }}`

lib/babel/transformation/file.js

@@ -59,7 +59,8 @@ File.helpers = [
   "object-destructuring-empty",
   "temporal-undefined",
   "temporal-assert-defined",
-  "tail-call"
+  "tail-call",
+  "self-global"
 ];
 
 File.validOptions = [

lib/babel/transformation/templates/named-func.js

@@ -0,0 +1,7 @@
+(function () {
+    function GET_OUTER_ID() {
+        return ID;
+    }
+
+    return FUNCTION;
+})()

lib/babel/transformation/transformers/index.js

@@ -91,6 +91,7 @@ module.exports = {
 
   "spec.typeofSymbol":                     require("./spec/typeof-symbol"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
+  "spec.functionName":                     require("./spec/function-name"),
 
   _moduleFormatter:                        require("./internal/module-formatter"),
 

lib/babel/transformation/transformers/spec/function-name.js

@@ -0,0 +1,53 @@
+"use strict";
+
+var t           = require("../../../types");
+var util        = require("../../../util");
+
+var propertyFunctionVisitor = {
+  enter: function (node, parent, scope, state, file) {
+    if (t.isReferencedIdentifier(node, parent, { name: state.name }) && scope.getBindingIdentifier(node.name) === state.binding) {
+      return state.getOuter();
+    }
+  }
+};
+
+exports.FunctionExpression = function (node, parent, scope, file) {
+  if (node.id) return;
+  var id;
+  if (t.isProperty(parent)) {
+    id = parent.key;
+  } else if (t.isVariableDeclarator(parent)) {
+    id = parent.id;
+  } else {
+    return;
+  }
+  var binding = scope.getBindingIdentifier(id.name);
+  var outerId, selfGlobalId;
+  scope.traverse(node, propertyFunctionVisitor, {
+    name: id.name,
+    binding: binding,
+
+    getOuter: function () {
+      if (!binding) {
+        return t.memberExpression(
+          selfGlobalId || (selfGlobalId = file.addHelper("self-global")),
+          id
+        );
+      }
+      return t.callExpression(
+        outerId || (outerId = scope.generateUidIdentifier("getOuter")),
+        []
+      );
+    }
+  });
+  node.id = id;
+  if (outerId) {
+    return util.template("named-func", {
+      GET_OUTER_ID: outerId,
+      ID:           id,
+      FUNCTION:     node
+    });
+  }
+};
+
+exports.optional = true;

test/fixtures/transformation/spec-function-name/actual.js

@@ -0,0 +1,27 @@
+var obj = {
+  f: function () {
+    (function f() {
+      console.log(f);
+    })();
+  },
+
+  g: function () {
+    console.log(g);
+  },
+
+  h: function () {
+    console.log(h);
+  },
+
+  m: function () {
+    doSmth();
+  }
+};
+
+var f = function () {
+  console.log(f, g);
+};
+
+var g = function () {
+  doSmth();
+};

test/fixtures/transformation/spec-function-name/expected.js

@@ -0,0 +1,42 @@
+"use strict";
+
+var _selfGlobal = typeof global === "undefined" ? self : global;
+var obj = {
+  f: function f() {
+    (function f() {
+      console.log(f);
+    })();
+  },
+
+  g: (function () {
+    function _getOuter() {
+      return g;
+    }
+
+    return function g() {
+      console.log(_getOuter());
+    };
+  })(),
+
+  h: function h() {
+    console.log(_selfGlobal.h);
+  },
+
+  m: function m() {
+    doSmth();
+  }
+};
+
+var f = (function () {
+  function _getOuter() {
+    return f;
+  }
+
+  return function f() {
+    console.log(_getOuter(), g);
+  };
+})();
+
+var g = function g() {
+  doSmth();
+};

test/fixtures/transformation/spec-function-name/options.json

@@ -0,0 +1,3 @@
+{
+  "whitelist": ["spec.functionName"]
+}